P. Khanenko, D. Hafner, K. Semeniuk, J. Banda, T. Lühmann, F. Bärtl, T. Kotte, J. Wosnitza, G. Zwicknagl, C. Geibel, J. F. Landaeta, S. Khim, E. Hassinger, M. Brando
{"title":"Origin of the non-Fermi-liquid behavior in CeRh2As2","authors":"P. Khanenko, D. Hafner, K. Semeniuk, J. Banda, T. Lühmann, F. Bärtl, T. Kotte, J. Wosnitza, G. Zwicknagl, C. Geibel, J. F. Landaeta, S. Khim, E. Hassinger, M. Brando","doi":"10.1103/physrevb.111.045162","DOIUrl":null,"url":null,"abstract":"Unconventional superconductivity in heavy-fermion systems appears often near magnetic quantum critical points (QCPs). This seems to be the case also for CeRh</a:mi>2</a:mn></a:msub>As</a:mi>2</a:mn></a:msub></a:mrow></a:math> (<b:math xmlns:b=\"http://www.w3.org/1998/Math/MathML\"><b:msub><b:mi>T</b:mi><b:mtext>c</b:mtext></b:msub><b:mo> </b:mo><b:mo>≈</b:mo><b:mn>0.31</b:mn></b:math> K). <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\"><c:mrow><c:msub><c:mi>CeRh</c:mi><c:mn>2</c:mn></c:msub><c:msub><c:mi>As</c:mi><c:mn>2</c:mn></c:msub></c:mrow></c:math> shows two superconducting (SC) phases, SC1 and SC2, for a magnetic field along the <d:math xmlns:d=\"http://www.w3.org/1998/Math/MathML\"><d:mi>c</d:mi></d:math> axis of the tetragonal unit cell, but only the SC1 phase is observed for a field along the basal plane. Furthermore, another ordered state (phase I) is observed below <e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\"><e:mrow><e:msub><e:mi>T</e:mi><e:mn>0</e:mn></e:msub><e:mo>≈</e:mo><e:mn>0.48</e:mn><e:mspace width=\"0.16em\"/><e:mi mathvariant=\"normal\">K</e:mi></e:mrow></e:math> whose nature is still unclear: Thermodynamic and magnetic measurements pointed to a nonmagnetic multipolar state, but recent <h:math xmlns:h=\"http://www.w3.org/1998/Math/MathML\"><h:mrow><h:mi>µ</h:mi><h:mi>SR</h:mi></h:mrow></h:math> and nuclear quadrupole resonance/nuclear magnetic resonance (NMR) experiments have clearly detected antiferromagnetic (AFM) order below <i:math xmlns:i=\"http://www.w3.org/1998/Math/MathML\"><i:msub><i:mi>T</i:mi><i:mtext>0</i:mtext></i:msub></i:math>. Also, quasi-two-dimensional AFM fluctuations were observed in NMR and neutron-scattering experiments above <j:math xmlns:j=\"http://www.w3.org/1998/Math/MathML\"><j:msub><j:mi>T</j:mi><j:mtext>0</j:mtext></j:msub></j:math>. The proximity of a QCP is indicated by non-Fermi-liquid (NFL) behavior observed above the ordered states in both specific heat <k:math xmlns:k=\"http://www.w3.org/1998/Math/MathML\"><k:mrow><k:mi>C</k:mi><k:mrow><k:mo>(</k:mo><k:mi>T</k:mi><k:mo>)</k:mo></k:mrow><k:mo>/</k:mo><k:mi>T</k:mi><k:mo>∝</k:mo><k:msup><k:mi>T</k:mi><k:mrow><k:mo>−</k:mo><k:mn>0.6</k:mn></k:mrow></k:msup></k:mrow></k:math> and resistivity <l:math xmlns:l=\"http://www.w3.org/1998/Math/MathML\"><l:mrow><l:mi>ρ</l:mi><l:mrow><l:mo>(</l:mo><l:mi>T</l:mi><l:mo>)</l:mo></l:mrow><l:mo>∝</l:mo><l:msqrt><l:mi>T</l:mi></l:msqrt></l:mrow></l:math>. These <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\"><m:mi>T</m:mi></m:math> dependencies are not compatible with any generic AFM QCP. Because of the strong magnetic-field anisotropy of both the SC phase and phase I, it is possible to study a field-induced SC QCP as well as a phase-I QCP by varying the angle <n:math xmlns:n=\"http://www.w3.org/1998/Math/MathML\"><n:mi>α</n:mi></n:math> between the field and the <o:math xmlns:o=\"http://www.w3.org/1998/Math/MathML\"><o:mi>c</o:mi></o:math> axis. Thus, by examining the behavior of the electronic specific-heat coefficient <p:math xmlns:p=\"http://www.w3.org/1998/Math/MathML\"><p:mrow><p:mi>C</p:mi><p:mo>(</p:mo><p:mi>T</p:mi><p:mo>)</p:mo><p:mo>/</p:mo><p:mi>T</p:mi></p:mrow></p:math> across these QCPs, we can determine which phase is associated with the NFL behavior. Here, we present low-temperature specific-heat measurements taken in a magnetic field as high as 21 T applied at several angles <q:math xmlns:q=\"http://www.w3.org/1998/Math/MathML\"><q:mi>α</q:mi></q:math>. We observe that the NFL behavior very weakly depends on the field and the angle <r:math xmlns:r=\"http://www.w3.org/1998/Math/MathML\"><r:mi>α</r:mi></r:math>, a result that is at odds with observations in standard magnetic QCPs. This suggests a nonmagnetic origin of the quantum critical fluctuations. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"74 1","pages":""},"PeriodicalIF":3.7000,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Physical Review B","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1103/physrevb.111.045162","RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"Physics and Astronomy","Score":null,"Total":0}
引用次数: 0
Abstract
Unconventional superconductivity in heavy-fermion systems appears often near magnetic quantum critical points (QCPs). This seems to be the case also for CeRh2As2 (Tc≈0.31 K). CeRh2As2 shows two superconducting (SC) phases, SC1 and SC2, for a magnetic field along the c axis of the tetragonal unit cell, but only the SC1 phase is observed for a field along the basal plane. Furthermore, another ordered state (phase I) is observed below T0≈0.48K whose nature is still unclear: Thermodynamic and magnetic measurements pointed to a nonmagnetic multipolar state, but recent µSR and nuclear quadrupole resonance/nuclear magnetic resonance (NMR) experiments have clearly detected antiferromagnetic (AFM) order below T0. Also, quasi-two-dimensional AFM fluctuations were observed in NMR and neutron-scattering experiments above T0. The proximity of a QCP is indicated by non-Fermi-liquid (NFL) behavior observed above the ordered states in both specific heat C(T)/T∝T−0.6 and resistivity ρ(T)∝T. These T dependencies are not compatible with any generic AFM QCP. Because of the strong magnetic-field anisotropy of both the SC phase and phase I, it is possible to study a field-induced SC QCP as well as a phase-I QCP by varying the angle α between the field and the c axis. Thus, by examining the behavior of the electronic specific-heat coefficient C(T)/T across these QCPs, we can determine which phase is associated with the NFL behavior. Here, we present low-temperature specific-heat measurements taken in a magnetic field as high as 21 T applied at several angles α. We observe that the NFL behavior very weakly depends on the field and the angle α, a result that is at odds with observations in standard magnetic QCPs. This suggests a nonmagnetic origin of the quantum critical fluctuations. Published by the American Physical Society2025
期刊介绍：
Physical Review B (PRB) is the world’s largest dedicated physics journal, publishing approximately 100 new, high-quality papers each week. The most highly cited journal in condensed matter physics, PRB provides outstanding depth and breadth of coverage, combined with unrivaled context and background for ongoing research by scientists worldwide.
PRB covers the full range of condensed matter, materials physics, and related subfields, including:
-Structure and phase transitions
-Ferroelectrics and multiferroics
-Disordered systems and alloys
-Magnetism
-Superconductivity
-Electronic structure, photonics, and metamaterials
-Semiconductors and mesoscopic systems
-Surfaces, nanoscience, and two-dimensional materials
-Topological states of matter
京公网安备 11010802042870号
京ICP备2023020795号-1
分享
求助内容：
应助结果提醒方式：
扫码关注我们
